This project is an innovative achievement in the field of green building energy-saving technology. It addresses the practical issues posed by the high-density trend commonly seen in large cities in China. Through the application of green energy-saving technologies for super-tall buildings in high-density urban environments, passive and active control design and technology for green energy-saving, green energy-saving design and technology for public spaces in high-density cities, the application of renewable urban energy sources, green energy-saving retrofitting techniques for existing buildings in high-density cities, outdoor environment optimization of existing neighborhoods, and ecological restoration techniques for urban environments, it provides strategies for the application and practice of related green energy-saving technologies in cities and architectural design. The high-density development of cities has become a major trend in the development of our country's large cities, while current architectural and urban green energy-saving design and technical analysis still remain at the exploratory stage of direction and guidance. There is a lack of strong technical support and methodological guidance at the practical level of technological application. In view of this, this project relies on the Key Laboratory of Ecological and Energy-saving Environment for High-density Human Settlements under the Ministry of Education, multiple national and provincial-level research fund projects, focusing on high-density urban environments. Under the premise of meeting comfort, it pays attention to the performance-based design of green and energy-saving buildings in high-density urban areas. A large number of researches and testing experiments, as well as important academic papers, have been conducted around high density and building green and energy-saving technologies. The important scientific and technological breakthroughs of the project are as follows: 1) Key technologies for building performance optimization in high-density urban environments; 2) Key technologies for green and energy-saving design of outdoor environments in high-density cities; 3) Key technologies for the renovation of existing buildings in high-density cities and urban environment transformation. The project has been authorized with one utility model patent, published two books, and more than 80 important academic papers in both domestic and international journals. The supporting achievement of this project — 'Research on MCDM and Performance Optimization Evaluation Methods for Green Energy-Saving Technologies in Ultra-High-Rise Buildings Responsive to the Environment' — as a key project funded by the TJAD Joint Research Center for Ecological and Energy Efficiency, is fully supported by Tongji University Architectural Design Institute (Group) Co., Ltd. The project's results have been applied in engineering projects of Tongji Design Institute and have spread nationwide and worldwide through these projects. They are widely used in the practice of green buildings and have also been extensively applied in the technical achievements of green buildings in other cities and regions, achieving good results. With continued promotion and application, it will generate greater economic and social benefits. The project results have promoted the development of architectural urban space environment design technology. It has also provided scientific and technical support for China's future improvement of residential energy-saving environments, with broad application prospects.